Cannabinoids

ABSTRACT

Compounds of the formula: wherein R, R1 and R4 are defined in the specification, and pharmaceutically acceptable salts, esters and tautomers thereof, having activity at peripheral cannabinoid receptors, commonly designated the CB2 receptor class. The compounds are useful for therapy, especially in the treatment of pain, inflammation and autoimmune disease.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to novel compounds that have activity atperipheral cannabinoid receptors, commonly designated the CB2 receptorclass. Particularly these compounds are more specific for said CB2receptor class than many other compounds active on cannabinoid receptorsCB1 and CB2.

At least five different classes of cannabinoids have been identified;traditional tricyclic tetrahydrocannabinoids, such asΔ⁹-tetrahydrocannabinoid (Δ⁹-THC), synthetic bicyclic cannabinoids suchas CP55,940 (see Little et al (1988)), aminoalkylindole such asWIN55,212 (see D'Ambra et al (1992)), endocannabinoid such as anandamide(see Devane et al (1992)), and pyrazole antagonists such as SR141716A(see Rinaldi-Carmona (1994)). Although the chemical structure of thesecannabinoids differ markedly, all of them contain at least one oxygenthat is hypothesized to be involved in binding of these drugs to braincannabinoid (CB1) receptors.

Δ⁹-THC, the primary psychoactive constituent of the marijuana plant, andother tetrahydrocannabinols contain two oxygens; a phenolic hydroxyl atposition 1 and an oxygen pyran ring on the opposite side of themolecule. The hydroxyl oxygen interacts with the CB1 receptor throughhydrogen bonding with a lysine residue (Lys 192) (see Song and Bonner(1996)). The role of the oxygen of the benzopyran substituent of Δ⁹-THCis less clear; however it is known that opening of the pyran ring as inCP55,940 does not eliminate binding or in vivo activity (See Little etal (1988)). In the absence of a phenolic hydroxyl, as in 1-deoxyanalogsof Δ⁸-THC, orientation of the cannabinoid molecule with respect to theCB1 receptor may be inverted and the pyran oxygen may substitute as asubstrate for hydrogen bonding with Lys 192 (see Huffman et al (1996),(1999)).

In contrast to the high binding affinity of CP55,940 and other similarpyran-ring open analogs the natural product cannabidiol is also apyran-ring open compound yet does not bind to CB1 or CB2 receptors nordoes it have a cannabinoid profile of effects in vivo. Even the1′,1′-dimethylheptyl analog of cannabidiol binds very poorly to the CB1receptor. With this in mind the present inventors have studied thestructural activity relationship of resorcinol derivatives which couldbe considered as cannabidiol analogs.

During this study, Hanu et al (1999) published synthesis and activity ofHU-3-8, a dimethoxyresorcinol derivative that is a CB2 selectiveagonist. The transmembrane regions of CB2 receptors, which are involvedin ligand recognition, exhibit 68% homology with those of CB1 receptors(see Munro et al (1993)). Showalter et al (1996) reported a highpositive correlation (r=0.82) between binding affinities at these twocannabinoid receptors for cannabinoids in various classes; thus some ofthe structural features that enhance affinity for CB1 also enhanceaffinity for CB2.

Addition of a 1′,1′-dimethyl group to the lipophilic C3 side chain ofΔ⁸-THC results in higher affinity for both receptors as compared to anonbranched chain of identical length. Synthesis of a series of Δ⁸-THCanalogs in which the phenolic hydroxyl at position 1 was removed(deoxy-Δ⁸-THC analogs) or was replaced with a methoxyl resulted inanalogs with selectivity for CB2 receptors (see Gareau et al (1996);Huffman et al (1996)(1999)). Incorporation of an oxygen into a fourthring attached at C1 also increased CB2 selectivity, suggestingdifferences in the interaction of oxygen in the binding pockets of CB1and CB2 (see Reggio et al (1997)).

The present inventors have now provided bicyclic resorcinols in whichthe core chemical structure contains two hydroxyl substituentspositioned with a single intervening carbon in a benzene ring with asecond cyclic substituent attached at the intermediate carbon.

In a first aspect of the present invention are provided novel compoundsof general formula I

wherein:

R is selected from the group consisting of optionally substitutedcarbocyclic and heterocyclic rings;

R1 is independently selected at each occurrence from the groupconsisting of hydrogen and C₁₋₆ alkyl;

R4 is selected from the group consisting of C₁₋₁₀ alkyl or alkenyl;

and pharmaceutically acceptable salts, esters and tautomers thereof.

Preferred compounds of the invention have R as optionally substitutedaryl, e.g. phenyl, cyclohexyl, cycloheptyl, cyclohexenyl, cyclopentyl,tetrahydrothiopyranyl, methandienyl, cycloheptyl, adamantanyl,tetrahydrothiophen-3-yl, 1-alkyl-piperidinyl, 4-aryl-cyclohexyl,3,3-dialkylcyclohexyl, tetrahydropyranyl, 1-cyclohexanolyl,1-4-dioxospirocycloalkyl, and cyclohex-3-enonyl.

Preferred compounds of the invention have R1 as hydrogen or methyl.

Preferred compounds of the invention have R4 as linear C₅₋₇ alkyl, e.g.,hexyl.

A preferred group of novel compounds of the first aspect of theinvention are of general formula II

wherein R1 and R4 are as described for formula I and R5 is C₁₋₆ alkyl,more preferably methyl or ethyl. More preferably R1 is hydrogen ormethyl, more preferably hydrogen. All isomers of compounds of formula IIare of interest, but particularly preferred are isomer A and isomer Band the 3R-alkylcyclohexyl compounds, particularly compounds of formula

-   -   2-(3-methylcyclohexyl)-5-(1,1′-dimethylheptyl)-resorcinol isomer        A (0-1797)    -   2-(3-methylcyclohexyl)-5-(1,1′-dimethylheptyl)-resorcinol isomer        B (0-1798)    -   2-(3R-methylcyclohexyl)-5-(1,1′-dimethylheptyl)-resorcinol        (0-1826).

A second aspect of the present invention provides a method of treating apatient in need of therapy for pain, particularly peripheral pain and/orinflammation or autoimmune disease comprising administering to thatpatient a therapeutically effective amount of a compound of formula I,more preferably of formula II. Such amount will typically beadministered in a pharmaceutically acceptable carrier, such as is wellknown in the art.

A third aspect of the present invention provides a compositioncomprising a compound of formula I or II together with apharmaceutically acceptable carrier and/or excipient. The compositionshould be sterile and, if intended for injection, non-pyrogenic.

Administration of the aforementioned compounds of the invention or aformulation thereof need not be restricted by route. Options includeenteral (for example oral and rectal) or parenteral (for exampledelivery into the nose or lung or injection into the veins, arteries,brain, spine, bladder, peritoneum, muscles or subcutaneous region). Thetreatment may consist of a single dose or a plurality of doses over aperiod of time. The dosage will preferably be determined by thephysician but may be between 0.01 mg and 1.0 g/kg/day, for examplebetween 0.1 and 500 mg/kg/day. In terms of dose per square meter of bodysurface, the compound can be administered at 1.0 mg to 1.5 g per m² perday, for example 3.0-200.0 mg/m²/day.

Whilst it is possible for a compound of the invention to be administeredalone, it is preferable to present it as a pharmaceutical formulation,together with one or more acceptable carriers and/or excipients. Thecarrier(s) and/or excipients must be “acceptable” in the sense of beingcompatible with the compound of the invention and not deleterious to therecipients thereof.

The formulations may conveniently be presented in unit dosage form andmay be prepared by any of the methods well known in the art of pharmacy.A unit dosage form may comprise 2.0 mg to 2.0 9, for example 5.0 mg to300.0 mg of active ingredient. Such methods include the step of bringinginto association the active ingredient, i.e., the compound of theinvention, with the carrier and/or excipients which constitute one ormore accessory ingredients. In general the formulations are prepared byuniformly and intimately bringing into association the active ingredientwith liquid carriers or finely divided solid carriers and/or excipientsand/or two or all of these, and then, if necessary, shaping the product.

Formulations in accordance with the present invention suitable for oraladministration may be presented as discrete units such as capsules,cachets or tablets, each containing a predetermined amount of the activeingredient; as a powder or granules; as a solution or a suspension in anaqueous liquid or a non-aqueous liquid; or as an oil-in-water liquidemulsion or a water-in-oil liquid emulsion. The active ingredient mayalso be presented as a bolus, electuary or paste.

A tablet may be made by compression or molding, optionally with one ormore accessory ingredients. Compressed tablets may be prepared bycompressing in a suitable machine the active ingredient in afree-flowing form such as a powder or granules, optionally mixed with abinder (e.g. povidone, gelatin, hydroxypropyl-methyl cellulose),lubricant, inert diluent, preservative, disintegrant (e.g. sodium starchglycollate, PVP, cross-linked povidone, cross-linked sodiumcarboxymethyl cellulose), surface-active or dispersing agent. Moldedtablets may be made by molding in a suitable machine a mixture of thepowdered compound moistened with an inert liquid diluent. The tabletsmay optionally be coated or scored and may be formulated so as toprovide slow or controlled release of the active ingredient thereinusing, for example, hydroxypropylmethylcellulose in varying proportionsto provide desired release profile.

Formulations suitable for topical administration in the mouth includelozenges comprising the active ingredient in a flavored basis, usuallysucrose and acacia or tragacanth; pastilles comprising the activeingredient in an inert basis such as gelatin and glycerin, or sucroseand acacia; and mouth-washes comprising the active ingredient in asuitable liquid carrier.

Formulations suitable for parenteral administration include aqueous andnon-aqueous sterile injection solutions which may contain anti-oxidants,buffers, bacteriostats and solutes which may render the formulationisotonic with the blood of the intended recipient; and aqueous andnon-aqueous sterile suspensions which may include suspending agents andthickening agents. The formulations may be presented in unit-dose ormulti-dose containers, for example sealed ampoules and vials, and may bestored in a freeze-dried (lyophilized) condition requiring only theaddition of the sterile liquid carrier, for example water forinjections, immediately prior to use. Extemporaneous injection solutionsand suspensions may be prepared from sterile powders, granules andtablets of the kind previously described.

Preferred unit dosage formulations are those containing a daily dose orunit, daily sub-dose or an appropriate fraction thereof, of an activeingredient.

It should be understood that in addition to the ingredients particularlymentioned above the formulations of this invention may include otheragents conventional in the art having regard to the type of formulationin question, for example those suitable for oral administration mayinclude flavoring agents.

In a fourth aspect of the present invention there is provide a compoundof the first aspect of the invention for use in therapy.

In a fifth aspect of the present invention there is provided the use ofa compound of the first aspect of the invention for the manufacture of amedicament for the treatment of a pain, inflammation and autoimmunedisease.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described further by reference to thefollowing non-limiting examples and Figures. These are provided for thepurpose of illustration only and other examples falling within the scopeof the claims will occur to those skilled in the art in the light ofthese. All literature references cited herein are incorporated byreference.

FIG. 1 shows Chemical structures of Δ⁹-THC, CP 55,940, and cannabidiol;

FIG. 2 shows a scheme for synthesis of resorcinol analogs;

FIG. 3 shows scatterplots and regression lines of log CB₁ K_(I) plottedagainst log CB₂ K_(I) (top left panel) and log ED₅₀ for each of thethree in vivo tests (SA=spontaneous activity, top right panel; MPE=%maximum possible antinociceptive effect, bottom left panel; RT=change inrectal temperature, bottom right panel); and

FIG. 4 shows a cannabinoid receptor (CB₂) selective resorcinolderivative.

DETAILED DESCRIPTION OF THE INVENTION

Subjects

Male ICR mice (25-32 g), obtained from Harlan (Dublin, Va.), were housedin groups of five. All animals were kept in a temperature-controlled(20-22° C.) environment with a 12-hour light-dark cycle (lights on at 7a.m.). Separate mice were used for testing each drug dose in the in vivobehavioral procedures. Brain tissue for binding studies was obtainedfrom male Sprague-Dawley rats (150-200 g) purchased from HarlanLaboratories (Dublin, Va.).

Apparatus

Measurement of spontaneous activity in mice occurred in standardactivity chambers interfaced with a Digiscan Animal Activity Monitor(Omnitech Electronics, Inc., Columbus, Ohio). A standard tail-flickapparatus and a digital thermometer (Fisher Scientific, Pittsburgh, Pa.)were used to measure antinociception and rectal temperature,respectively.

Compounds

Resorcinols were synthesized in our labs (Organix, Inc., Woburn, Mass.)according to the procedure specified below and were suspended in avehicle of absolute ethanol, Emulphor-620 (Rhone-Poulenc, Inc.,Princeton, N.J.), and saline in a ratio of 1:1:18. Drugs wereadministered to the mice intravenously (i.v.) in the tail vein at avolume of 0.1 ml/10 g.

Analogs O-1376 and O-1532 listed in Table 1 were synthesized aspreviously described (Mahadevan et al., 2000). Analog O-1601 wassynthesized from 1-deoxy-9-carbomethoxy cannabinol DMH analog (Mahadevanet al., 2000) by lithium/liquid ammonia reduction as described for thepreparation of O-1376. The compounds listed in Tables 2 and 3 wereprepared using a three step sequence (FIG. 1). The 2-lithio derivativeof 1,3-dimethoxy-5-(1′,1′-dimethylheptyl) resorcinol (1) was preparedusing n-BuLi/hexane in THF. It was condensed with the appropriate ketoneto give the tertiary alcohol 2, which on treatment with trifluoroaceticacid/Et3SiH gave the dimethoxy precursors 3. Demethylation² withBBr₃/CH₂Cl₂ gave the target compounds (Crocker et al., 1999). Thegeneral procedure is illustrated in FIG. 2 and described below.

To a solution of the resorcinol 1, (5 mmol) in 25 ml of dry THF wasadded a 2.5 M solution of n-BuLi in hexane (5.5 mmol) at 0° C. withstirring/N₂. After additional stirring for 1 h at 0° C., added asolution of the ketone (7.5 mmol) in 3 ml of dry THF all at once. Thesolution was stirred for 0.5 h at 0° C. and then at 23° C. for 18 h. Thereaction was worked up by the addition of sat NH₄Cl solution andextracted with ether. After washing (H₂O) and drying (Na₂SO₄) thesolvent was evaporated to give the crude tertiary alcohol 2, which wasused as such in the subsequent reaction. A solution of the tertiaryalcohol 2 (5 mmol) in 10 ml of dry CH₂Cl₂ was treated with CF₃COOH (27.5mmol) followed by Et₃SiH (12.5 mmol). The solution was stirred/N₂ for 1h or more (followed by TLC) and then quenched by the addition of satNaHCO₃ solution. The organic layer was separated and after washing (H₂O)and drying gave the crude dimethoxy precursor 3 of the target compound.This material was used as such for the demethylation step. Treatment of3, as a solution in dry CH₂Cl₂ at 0° C., with 3 equivalents of 1 N BBr₃solution in CH₂Cl₂, using the standard procedure and work up², gave thecrude target compound, which was purified by chromatography, generallyusing hexane/ethyl acetate mixtures. In the case of O-1662 (Table 2),the corresponding tertiary alcohol 2 on treatment with CF₃COOH/Et₃SiHgave the unsaturated compound (dehydrated but not reduced) which oncatalytic reduction (PtO₂/C/H₂) in acetic acid gave the desireddimethoxy precursor 3. The final compound was purified by chromatographyusing 5% Et₃NH₂/EtOAc mixture. The unsaturated analog O-1423 (Table 2)was prepared by treatment of the corresponding tertiary alcohol 2 withCF₃COOH alone in CH₂Cl₂ followed by demethylation. In Table 3, compoundsO-1797-A and O-1798-B were diastereomeric mixtures and showed as twodistinct spots in TLC which were separated by column chromatography,whereas O-1657 was a sample of the mixture of diastereomers O-1797-A andO-1798-B. The dimethoxy compounds listed in Tables 4 and 5 were prepared(FIG. 2) from 1 and the appropriate ketones using BuLi, as in thepreparation of 2, and isolating and purifying the compounds bychromatography (ethyl acetate/hexane mixtures). Deprotection of O-2092was carried out by treatment with 10% HCl in a ether/THF (5:4) mixturefor 0.5 h at 23° C. to give a mixture of O-2115 (major) and thedehydrated compound O-2114 (minor). Sodium borohydride reduction ofO-2115 furnished a mixture of diastereomeric compounds which wereseparated by chromatography to give the target compounds O-2116-A andO-2117-B. Similarly O-1966-A and O-1967-B were separated from adiastereomeric mixture by chromatography. Epoxidation of O-2114 followedby NaBH₄ reduction gave the target compound O-2122. In the preparationof O-2090 the corresponding diethoxy resorcinol derivative of 1 was usedin place of 1. All compounds showed appropriate ¹HNMRs (Jeol Eclipse 300MHz) and were characterized on the basis of their ¹HNMRs, TLC, andelemental analyses.

Mouse Behavioral Procedures

Prior to testing in the behavioral procedures, mice were acclimated tothe experimental setting (ambient temperature 22-24° C.) overnight.Pre-injection control values were determined for rectal temperature andtail-flick latency (in sec). Five min after i.v. injection with drug orvehicle, mice were placed in individual activity chambers andspontaneous activity was measured for 10 min. Activity was measured astotal number of interruptions of 16 photocell beams per chamber duringthe 10-min test and expressed as % inhibition of activity of the vehiclegroup. Tail-flick latency was measured at 20 min post-injection. Maximumlatency of 10 sec was used. Antinociception was calculated as percent ofmaximum possible effect {% MPE=[(test−controllatency)/(10-control)]×100}. Control latencies typically ranged from 1.5to 4.0 sec. At 30 min post-injection, rectal temperature was measured.This value was expressed as the difference between control temperature(before injection) and temperatures following drug administration (°C.). Different mice (n=5-6 per dose) were tested for each dose of eachcompound. Each mouse was tested in each of the 3 procedures.

CB₁ Binding Procedure

The methods used for tissue preparation and binding have been describedpreviously (Compton et al., 1993) and are similar to those described byDevane et al. (1988). All assays, as described briefly below, wereperformed in triplicate, and the results represent the combined datafrom three to six individual experiments.

Following decapitation and rapid removal of the brain, whole brain washomogenized and centrifuged. The resulting pellet was termed P₁. Thesupernatant was saved and combined with the two subsequent supernatantsobtained from washing of the P₁ pellet. The combined supernatantfractions were centrifuged, resulting in the P₂ pellet. After furtherincubation and centrifuging, this pellet was resuspended in assay bufferto a protein concentration of approximately 2 mg/ml. The membranepreparation was quickly frozen in a bath solution of dry ice and2-methylbutane (Sigma Chemical Co., St. Louis, Mo.), then stored at −80°C. for no more than 2 weeks. Prior to performing a binding assay analiquot of frozen membrane was rapidly thawed and protein valuesdetermined by the method of Bradford (1976).

Binding was initiated by the addition of 150•g of P₂ membrane to testtubes containing 1 nM of [³H] CP 55,940 (79 Ci/mmol) and a sufficientquantity of buffer to bring the total incubation volume to 1 ml.Nonspecific binding was determined by the addition of 1•M unlabeled CP55,940. Following incubation at 30° C. for 1 hr, binding was terminatedby addition of ice cold buffer and vacuum filtration through pretreatedfilters in a 12-well sampling manifold (Millipore, Bedford, Mass.).After washing, filters were placed into plastic scintillation vials(Packard, Downer Grove, Ill.) and shaken. The quantity of radioactivitypresent was determined by liquid scintillation spectrometry.

CB₂ Binding Procedure

Membranes for CB₂ binding were obtained from CHO cells. The transfectedcell line was maintained in Dublecco's Modified Eagle Medium (Gibco BRL,Grand Island, N.Y.) with 10% fetal clone II (HyClone Laboratories, Inc.,Logan, Utah) plus 0.3 to 0.5 mg/ml G418 (to maintain selective pressure)under 5% CO₂ at 37% C. Cells were harvested with 1 mM EDTA inphosphate-buffered saline and were centrifuged at 1000×g for 5 min at 4%C. The supernatant was saved and the P1 pellet was resuspended incentrifugation buffer. Homogenization and centrifugation were repeatedtwice and the combined supernatant fractions were centrifuged at40,000×g for 30 min at 4% C. The P2 pellet was resuspended incentrifugation buffer 2 (Tris HCl, 50 mM; EDTA, 1 mM; and MgCl₂, 3 mM,pH 7.4) to a protein concentration of approximately 2 mg/ml. Proteinconcentrations were determined by the method of Bradford (1976) usingBio-Rad Protein Assay (Bio-Rad, Richmond, Calif.) and BSA standards(fatty acid free, Sigma Chemical Co., St. Louis, Mo.). The membranepreparation was divided into amounts convenient for binding assays andfrozen rapidly in dry ice and stored at −80% C.

Binding was initiated by the addition of 50•g of quickly thawed P2membranes to test tubes containing [³H]CP-55,940 (final reactionconcentration 0.5 nM), an appropriate concentration of unlabeledCP-55,940 or test drug, and sufficient quantity of assay buffer (50 mMTris-HCl, 1 mM EDTA, 3 mM MgCl₂, 5 mg/ml bovine serum albumin, pH 7.4)to bring the total incubation volume to 0.5 ml. Concentration of[³H]CP-55,940 in saturation studies ranged from 50 to 10,000 pM.Nonspecific binding was determined by the addition of 1•M unlabeledCP-55,940. CP-55,940 and all cannabinoid analogs were-prepared bysuspension in assay buffer from a 1 mg/ml ethanolic stock withoutevaporation of the ethanol (final concentration of no more than 0.4%).In competition studies, analog concentrations ranged from 0.1 nM to10•M. After incubation at 30% C for 1 hr, binding was terminated by theaddition of 2 ml of ice-cold wash buffer (50 mM Tris-HCl and 1 mg/mlBSA) and vacuum filtration through pre-treated filters in a 12-wellsampling manifold (Millipore, Bedford, Mass.). Reaction vessels werewashed once with 2 ml of ice-cold wash buffer. Filters were placed into7-ml plastic scintillation vials (RPI Corp., Mount Prospect, Ill.) with4 ml of Budget-Solve (RPI Corp.). After shaking for 30 min, theradioactivity present was determined by liquid scintillationspectrometry. Three reaction vessels were used for each drugconcentration in each assay. The results represent the combined data ofthree independent experiments. All assays were performed in siliconizedtest tubes, which were prepared by air drying (12 hr) invertedborosilicate tubes after two rinses with a 0.1% solution of AquaSil(Pierce, Rockford, Ill.). The GF/C glass-fiber filters (2.4 cm, Baxter,McGaw Park, Ill.) were pre-treated in a 0.1% solution of pH 7.4polyethylenimine (Sigma Chemical Co.) for at least 6 hr.

Data Analysis

Based on data obtained from numerous previous studies with cannabinoids,maximal cannabinoid effects in each procedure were estimated as follows:90% inhibition of spontaneous activity, 100% MPE in the tail flickprocedure, and −6° C. change in rectal temperature. ED₅₀'s were definedas the dose at which half maximal effect occurred. For drugs thatproduced one or more cannabinoid effect, ED₅₀'s were calculatedseparately using least-squares linear regression on the linear part ofthe dose-effect curve for each measure in the mouse tetrad, plottedagainst log₁₀ transformation of the dose. For the purposes of potencycomparison, potencies were expressed as μmol/kg.

Pearson product-moment correlation coefficients (with associatedsignificance tests) were calculated between CB₁ binding affinity(expressed as log K_(i)) and in vivo potency for each measure (expressedas log ED₅₀ in μmol/kg) for all active cannabinoid compounds that boundto the CB₁ receptor. In addition, multiple linear regression was used tocalculate the overall degree of relationship between CB₁ bindingaffinity and potency in the mouse measures for all active cannabinoids.A correlation between CB₁ and CB₂ binding affinities was calculated forall compounds that had measurable K_(I)'s for CB₁ and CB₂ binding(K_(i)<10,000 nM). Ki values for CB₁ and CB₂ binding were obtained fromScatchard displacement analysis as determined via EBDA program of theKELL software package (Biosoft, Milltown, N.J.).

The CB₁ and CB₂ binding affinities for substituted biphenyl analogs areshown in Table 1. These compounds contain a phenolic hydroxyl and alipophilic side chain in the same orientation as in cannabinol. Inaddition, the pyran oxygen is absent and the analogs have substituentsin the phenyl ring (ring C) of cannabinol. Two of the analogs (O-1376and O-1601) have a dimethylheptyl side chain; each possessed good CB₁and CB₂ binding affinities and in vivo activity. O-1601, the more potentof the two active compounds, had a hydroxymethyl group in the phenylring. This substitution increased CB₁ affinity and in vivo potenciescompared to O-1376, but did not affect affinity for CB₂ receptors. Asimilar effect is observed in the cannabinol series where thesubstitution of a hydroxymethyl group for a methyl at C-9 in cannabinolincreased binding affinity and potency (Mahadevan et al., 2000).Shortening the side chain of O-1376 to dimethylbutyl (O-1532) severelydecreased affinity for both receptors and resulted in loss of in vivoactivity.

Table 2 presents binding and in vivo data for a series of 2-cyclic ringsubstituted-5-dimethylheptyl resorcinols. Manipulation of the size ofthe cyclic structure attached at position 2 of the resorcinol ringresulted in changes in binding affinities and potencies. Substitution ofa cyclopentane ring (O-1424) resulted in moderate affinity for the CB₁receptor with excellent affinity for the CB₂ receptor. Although thiscompound was active in all three in vivo assays, potency was relativelypoor. In addition, potencies across the measures were not equal; i.e.,potency for reducing spontaneous activity was approximately half thatfor producing antinociceptive and hypothermic effects. Increasing ringsize to a cyclohexane (O-1422), cycloheptane (O-1656), or adamantyl(O-1660) improved affinity 5- to 14-fold for both cannabinoid receptorsand greatly increased potencies in vivo. Substitution of a sulfur for acarbon in a cyclohexane ring (O-1425) decreased CB₁ affinity by 14-foldand CB₂ affinity by 8-fold (compared to O-1422) as well as reducing invivo potencies. Similarly, sulfur substitution in a cyclopentane ring(O-1661) also attenuated binding to both cannabinoid receptors. When amethylated nitrogen (O-1662) was inserted into the cyclohexane ring inthe same position as the sulfur of O-1425, binding to CB₁ receptors didnot occur. In addition, CB₂ binding was drastically decreased and thecompound was not fully active in vivo. In contrast, placing a doublebond in the cyclohexane ring (O-1423) decreased affinities andpotencies, but the compound remained active. However, moving thelipophilic side chain of O-1422 from C-5 to C-4 and replacing the DMHwith a n-hexyl chain (O-2010) produced a 865-fold decrease in CB₁affinity and a loss of activity in vivo.

Table 3 shows results of tests with cyclohexane substituted resorcinolsin which the position of the substituent at the cyclohexane ringattached to the core resorcinol was varied. All compounds werediastereomeric mixtures. All of these analogs had good (K_(i)=2 nM) tomoderate (K_(i)=144 nM) affinity for CB₁ receptors and wereCB₂-selective (K_(i)range=0.3-13 nM). Methylation at the 2 position ofthe cyclohexane ring (O-1658) did not dramatically alter affinity foreither cannabinoid receptor or in vivo potencies compared to thecorresponding cannabinoid with a non-methylated cyclohexane (O-1422 inTable 2). Moving the methyl to position 4 of the cyclohexane ring(O-1659) decreased affinity for both cannabinoid receptors by about5-fold and produced an even greater decrease (11- to 24-fold) inpotencies in vivo. Substituting a phenyl group for the methyl at thissame position (O-1663) resulted in 2- to 3-fold decreases in CB₂ and CB₁affinities, respectively, and a loss of activity in vivo. In the nextfive analogs shown in Table 3, the methyl was attached at position 3 ofthe cyclohexane ring. O-1657 exhibited CB₁ and CB₂ affinities that weresimilar to those of O-1658; however, the profiles of in vivo potenciesdiffered. Whereas the two analogs showed approximately equal potenciesin suppressing spontaneous activity, O-1658 was twice as potent inproducing antinociception and three times as potent in reducing bodytemperature. By careful chromatography, compound O-1657 was separatedinto two distinct entities which were designated O-1797-A and O-1798-B.These analogs were still mixtures. Affinities of O-1797-A and O-1798-Bwere 2-3 times greater than those of O-1657. While potencies of theseisomers for suppression of locomotor activity and hypothermia were notnotably different from those of O-1657, antinociceptive potencies werereduced by about half. The 3R isomer of this series (O-1826) showeddecreased affinity for CB₁ receptors compared to O-1657; however,affinity for CB₂ receptors was identical for both compounds. Notsurprisingly, given its decreased CB₁ affinity, O-1826 was less potentthan O-1657 in vivo. Substitution of a dimethylbutyl for the DMH sidechain at C5 of the resorcinol component (O-1890) decreased affinitiesfor both cannabinoid receptors. This compound was active in vivo,although potency was notably low for all measures. In contrast, additionof a gem-dimethyl group at the 3 position of the cyclohexane ring withretention of the DMH side chain of the resorcinol component (O-1871)resulted in the best CB₁ and CB₂ affinities of this series. In vivopotencies, however, were lower than expected for this compound, givenits higher CB₁ binding affinity.

In order to develop CB₂ selective ligands, we examined cyclic ringsubstituted dimethoxy resorcinols. The CB₁ and CB₂ binding affinities ofthese analogs are shown in Tables 4 and 5. Although most of thecompounds shown in Tables 4 and 5 possessed a dimethylheptyl side chain,all had poor CB₁ affinity; hence, they were not tested in vivo. Thebicyclic structure of O-1999 (Table 4) was almost identical to that ofO-1657 (Table 3), an analog with good CB₁ and CB₂ affinities and potentin vivo effects. Both compounds had a dimethylheptyl side chain attachedto the 5 position of a resorcinol core that was attached at position 2to a cyclohexane ring. Each compound had a methyl group at the 3position of the cyclohexane ring. The major structural differencebetween the two compounds was that O-1999 was a dimethoxy derivative ofthe resorcinol O-1657. This seemingly minor structural change from aphenol to a methoxy derivative resulted in complete loss of affinity forCB₁ receptors and an almost 600-fold reduction in affinity for CB₂receptors. Similarly, the other analogs that were dimethoxy derivativesof the corresponding resorcinols had poor affinity for CB₁ receptors(K_(i) ranged from 1716 to >10,000), regardless of the cyclic ringsubstitution at position 2. In contrast, CB₂ binding affinities for someof these analogs remained high, as described in more detail below.

Table 4 presents binding data for 2-cyclic ring substituteddimethoxy-resorcinol-DMH analogs that contain at least one oxygeninserted into or attached to the non-resorcinol cyclohexane ring.Compared to O-1999 which did not contain an oxygen in the cyclohexanering, conversion of the cyclohexane ring to a pyran ring (O-1964)decreased CB₂ affinity almost 2-fold without effect on CB₁ binding.Further addition of a double bond at position 3 of the pyran ringresulted in O-1965 which did not bind to either cannabinoid receptor. Incontrast, the introduction of a tertiary hydroxyl group at C-4 of thepyran ring (O-1962) increased CB₂ affinity by 3-fold. Adding additionaloxygens such as a ketol group attached at C-4 to the point of attachmentof the dimethoxy resorcinol substituent (O-2092) also increased CB₂affinity whereas adding an oxygen as an epoxide (O-2122) decreased it.The presence of a ketone group at C-4 of the cyclohexane ring and havingunsaturation in the ring (O-2114) resulted in a compound with pooraffinity for either cannabinoid receptor; however, if a tertiaryhydroxyl group was added at the site of dimethoxy resorcinol attachment(O-2115), CB₂ affinity improved. Retention of the tertiary hydroxyl,methylation at position 5 and the presence of a ketone at position 3 ofthe cyclohexane ring increased affinity for both receptors and resultedin a compound (O-2123) with the best affinity (K_(i)=125 nM) in thisseries.

Table 5 shows CB₁ and CB₂ affinities for 2-cyclic ring substituteddimethoxy-resorcinol-DMH analogs in which the ring size and the positionof the methyl or hydroxyl substituent on the cyclohexane ring arevaried. The first analog (O-2072) contains one hydroxyl attached to thecyclohexane at the same position at which the resorcinol core isattached. This compound is CB₂-selective. While it had poor affinity forCB₁ receptors, it bound with moderate affinity to CB₂ receptors.Introduction of a methyl substituent in the 3 position of thecyclohexane ring gave a diastereomeric mixture from which two distinctentities were separated by careful chromotography. These analogs(O-1966-A and O-1967-B) were still mixtures. This substitution resultedin a 5-fold increase in affinity for CB₂ receptors with continued pooraffinity for CB₁ receptors. However, one of these isomers (O-1966-A)showed the best CB₂ selectivity (225-fold) in the series and had highbinding affinity for the CB₂ receptor (K₁=22.5 nM). Addition of an extrahydroxyl group to the cyclohexane ring (O-2121) reduced both selectivityand binding affinity for the CB₂ receptor comparable to those obtainedwith O-1967-B. Removal of the methyl at position 3 and addition of anhydroxyl at position 4 resulted in two diastereomeric mixtures whichcould be separated that were designated as O-2116-A and O-2117-B. Bothof these isomers had poor affinity for CB₁ receptors, but while the Bisomer also had poor affinity for CB₂ receptors, the A isomer bound toCB₂ receptors with moderate affinity. Attachment of a gem-dimethyl groupto position 3 of O-2072 (i.e., O-2068) did not significantly alteraffinities for CB₁ or CB₂ receptors; however, replacement of the DMHgroup of O-2068 with a methyl group (O-2139) produced loss of affinityat both receptors. Changing the dimethyoxy groups of the resorcinol byadding diethoxy groups (O-2090) drastically decreased affinities for CB₁and CB₂ receptors (compare O-2090 to O-1966-A or O-1967-B). Enlargingthe cyclohexane ring in O-2072 to a cycloheptane ring (O-2091) resultedin little change in affinity for CB₁ receptors and an almost 2-foldincrease in CB₂ affinity.

As stated in the introduction, the lack of CB₁ binding affinity ofcannabidiol compared to other pyran-ring open analogs such as CP 55,940prompted us to examine the structure-activity relationships ofresorcinol derivatives for in vitro and in vivo cannabinoid activity.Our results show that many of the structural changes that affect CB₁receptor recognition and activation in traditional bicyclic andtricyclic cannabinoids similarly alter binding and activity in thisresorcinol series. Previous research has shown that the length andbranching of a lipophilic substituent is important for CB₁ receptorrecognition in all of the major cannabinoid agonist classes, includingtetrahydrocannabinols (Compton et al., 1993), bicyclic cannabinoids(Compton et al., 1993), indole-derived cannabinoids (Wiley et al.,1998), and anandamides (Ryan et al., 1997; Seltzman et al., 1997). Inthe tricyclic and bicyclic series, a 1′,1′-dimethylheptyl side chain isoptimal (Compton et al., 1993) and is contained in most of theresorcinols presented here. Reducing the length of this substituent to1′,1′-dimethylbutyl (O-1532 and O-1890) or methyl (O-2139) or a hydrogen(O-2010) resulted in a concomitant elimination or decrease in CB₁receptor recognition, as occurs in other cannabinoid series with similarstructural manipulations (see references above).

Other structural features affecting CB₁ receptor recognition andactivation in this resorcinol series are related to the size,saturation, substitution, and methylation of the second, non-resorcinolring of these bicyclic cannabinoids. In most tricyclic and bicycliccannabinoids, the ring corresponding to the non-resorcinol ring in thecurrent series is a cyclohexane. Reducing this size to a cyclopentanedecreases CB₁ affinity and potency whereas increasing it to acycloheptane has little effect. Substitution of an adamantyl results inbetter CB₁ affinity; however, potency is decreased. Similarmodifications of tricyclic and bicyclic cannabinoids have not beenreported. The degree of saturation of the cyclohexane ring, however, hasbeen manipulated in several cannabinoid classes. In the resorcinolseries, the presence of a cyclohexane ring appeared optimal, although athorough investigation of this issue was not undertaken. Introduction ofa single double bond (O-1423) within the ring decreased CB₁ affinity andpotency to the same extent as did a reduction in the size of the ring toa cyclopentane. Hence, most structural manipulations were performed upona bicyclic resorcinol-cyclohexane template. Degree of saturation of, aswell as the position of the double bond in the cyclohexane ring oftricyclic and bicyclic cannabinoids and in the polyolefin loop of theanandamides, has also been shown to affect CB₁ receptor recognition andactivity in these cannabinoid classes. Greatest affinity and potencywithin the anandamides is achieved with four double bonds, with greateror lesser saturation resulting in a reduction in CB₁ binding and/or invivo activity (Adams et al., 1995; Sheskin et al., 1997; Thomas et al.,1996). Similarly, number and position of double bonds within thecyclohexane ring of tetrahydrocannabinols and bicyclic cannabinoidsaffect activity. For example, moving the double bond of Δ⁹-THC toposition Δ⁸ (as in Δ⁸-THC) decreases CB₁ affinity three-fold andsomewhat reduces potency (Compton et al., 1993). Unsaturation of thecyclohexane ring results in cannabinol with its greatly reduced CB₁affinity (Showalter et al., 1996). In contrast, CP 55,940, with acompletely saturated cyclohexane ring, is several fold more potent thanΔ⁸-THC-DMH which has a single double bond in the cyclohexane ring, butΔ⁸-THC with its single double bond binds with better CB₁ affinity thandoes Δ⁹⁽¹¹⁾-THC which has a completely saturated cyclohexane ring(Compton et al., 1993).

The most remarkable structural features of the resorcinol seriesaffecting CB₁ affinity, however, are the length of the lipophilic sidechain at position 5 and the size of the cyclic ring substituent atposition 2 of the resorcinol core. THC and CP 55,940 contain twooxygens: one as a phenol (one hydroxyl in the aromatic ring) with asecond oxygen incorporated into a separate ring (pyran oxygen in THC) ora hydroxyl group attached as a substituent in the cyclohexane ring as inCP 55,940. Previous research has shown that eliminating the phenolichydroxyl of Δ⁸-THC-like cannabinoids results in deoxy-THC analogs thatare CB₂-selective (Huffman et al., 1999). Although some of thesedeoxy-THC analogs also retain reasonable affinity for CB₁ receptors,orientation of their binding to CB₁ receptors may be inverted such thatthe pyran oxygen substitutes for the absent phenolic hydroxyl inhydrogen bonding (Huffman et al., 1996). In the absence of a pyranoxygen, as in the resorcinols, the nature of the substituent at position2 of the resorcinol core is important to maintain adequate CB₁ affinityfor in vivo activity. An acyclic ring was found to be better than aheterocyclic ring with a cyclohexane ring being optimal for in vivoactivity. In addition, the size and the position of the substituent onthe cyclic ring is important to maintenance of CB₁ affinity. Thepresence of a methyl substituent at position 3 enhanced activity in somecases. Further, the 3R analog (O-1826; Table 2) has a poorer. CB₁binding affinity (K_(I)=40 nM) compared to the diastereomeric mixtureO-1657 (K_(I)=14 nM; Table 2), suggesting that CB₁ binding affinity isenhanced when the orientation of the methyl substituent at position 3 inthe cyclohexane ring is 3S compared to 3R. Methylation of the phenols ofthe resorcinols drastically decreased or eliminated CB₁ affinity,perhaps because hydrogen donation is less likely from a methoxy groupthan from THC's free hydroxyl group (B. R. Martin, unpublishedobservations). Similarly, methoxy substitution for the phenolic hydroxylin the methyl esters of Δ⁸- and Δ⁹⁽¹¹⁾-THC-DMH resulted in analogs thatwere CB₂-selective and had little affinity for CB₁ receptors (Gareau etal., 1996; Huffman et al., 1999; Ross et al., 1999).

Notably, with the exception of a few compounds, the dimethoxyresorcinolstested here were CB₂-selective. Most of the structural features thataffected recognition at CB₁ receptors also affected CB₂ receptorrecognition, although not always to the same degree or in the samemanner. These factors included length and branching of the side chainand size and degree of saturation of the non-resorcinol cyclohexanering. In a SAR study on a series of CB₂-selective deoxy-Δ⁸-THC analogs,Huffman et al. (1999) reported that length and branching of the C3 sidechain affected CB₂ binding in a manner similar to its effect on CB₁affinity, as it did in the present study; however, the range of chainlengths for which moderate to good CB₂ affinity was retained for thedeoxy-Δ⁸-THC analogs was greater than the range for CB₁ affinity.Similar results were obtained with a series of CB₂-selectiveindole-derived cannabinoids in which length of the nitrogen substituentwas varied (Aung et al., 2000). To date, anandamide analogs appear to beCB₁-selective with relatively little affinity for CB₂ receptors acrossseveral types of manipulations (Showalter et al., 1996). Insufficientresearch is available to determine the effect of substitution on acyclohexane ring on CB₂ affinity across cannabinoid classes.

Other structural manipulations eliminated or drastically reduced CB₁receptor recognition, but did not necessarily alter CB₂ receptor bindingin an identical manner. As mentioned, CB₂ selectivity was most evidentin the dimethoxy analogs, primarily as a consequence of severereductions in CB₁ affinity. HU-308, the most selective CB₂ agonist todate, has a dimethoxy resorcinol core structure and does not bind to CB₁receptors at all (Hanu_et al., 1999). In addition, greater tolerance inCB₂ (vs. CB₁) receptor recognition was observed with other C2substitutions in the resorcinols. Huffman et al. (2001) recentlyreported that bicyclic pyridone analogs with carbonyl substitution at C1and a nitrogen substituent substitution at C2 of THC had little affinityfor CB₁ receptors. In contrast, moderate CB₂ affinity (Ki=53 nM) wasretained. Differences in allosteric regulation of CB₁ and CB₂ receptorsby ions and guanine nucleotides has been noted previously (Showalter etal., 1996). Together, results presented here and elsewhere (see above)suggest incomplete overlap of the pharmacophores for CB₁ and CB₂receptors.

In summary, structure-activity relationships of the resorcinol seriespresented here are consistent with the CB₁ and CB₂ pharmacophores ofother cannabinoid classes, including tetrahydrocannabinols, bicycliccannabinoids, aminoalkylindoles, and anandamides. In this series ofresorcinols, several structural features were essential for maintenanceof CB₁ receptor recognition and in vivo activity, including the presenceof a branched lipophilic side chain (DMH) at C5, the presence of freephenols, and substitution of a cyclohexane ring at C2. An importantstructural feature for receptor recognition at CB₂ receptors was sidechain length, as reduction of the chain length to a methyl eliminatedCB₂ binding affinity. The CB₂ selectivity observed with some resorcinolswas maximized in the dimethoxyresorcinol analogs and this selectivitywas greatly enhanced when a tertiary hydroxyl group was present in thecyclohexane ring in the same position at which the resorcinol core isattached. In contrast, the presence of unsaturation or a ketone group oran additional hydroxyl substitution in the cyclohexane ring adverselyaffected the CB₂ selectivity. Methyl ethers were optimal for CB₂selectivity since ethyl ethers reduced selectivity.

In conclusion, although resorcinol derivatives with cyclic ringsubstituents at C2 are closely related to the nonactive cannabinoidcannabidiol, many of these analogs have high CB₁ and/or CB₂ bindingaffinity as well as potent in vivo activity. In addition, becausedimethoxyresorcinols are CB₂ selective, they have potential to offerinsight into similarities and differences between requirements forreceptor recognition at CB₁ versus CB₂ receptors. One such differencenoted here was the greater tolerance found for substitution at position2, in the resorcinol series, for CB₂ receptor recognition compared tothat for CB₁ receptors. The results presented here suggest that theresorcinol series represent a novel template for the development of CB₁and CB₂ selective cannabinoid agonists.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

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The disclosures of all of the above-cited references are incorporatedherein by reference. TABLE 1 CB₁ and CB₂ Binding Affinities andPharmacological Effects of Phenols

K_(i)(nM) ED₅₀ ID R R1 CB₁ CB₂ CB₁/CB₂ SA TF RT 1 O-1376 CH₃ DMH 33 ± 43 ± 0.4 11 8.5 5.7 23 (5-16) (3-10) (1-5) 2 O-1532 CH₃ DM-buryl 876 ± 18113 ± 21 8 32% 7% −0.4 (30) (30) (30) 3 O-1601 CH₂OH DMH   5 ± 0.6 3 ±0.4 2 1.1 1.1 1.6 (0.8-1.4) (0.8-1.4) (1.4-2.2)The K_(i)'s presented as means ± SEM. All ED₅₀'s are expressed asμmol/kg (with 95% confidence limits in parentheses). For Compounds thatfailed to produce either maximal or dose-related effects, the percenteffect at the highest dose (mg/kg: in parenthesis) is provided. SA =suppression of spontaneous activity; MPE - % maximum possibleantinociceptive effect in tail flick assay; RT = rectal temperature. DMH= dimethylheptyl.

TABLE 2 Pharmacological Effects and Cannabinoid Receptor Binding:Affinities of Bicyclic Resorcinols

K_(i)(nM) CB₁/ ED₅₀ ID R R1 R2 CB₁ CB₂ CB₂ SA TF RT O-1424

DMH H 95 ± 6   7 ± 0.4 14  27  (13-56) 13  (9-23) 13  (10-20) O-1422

DMH H 11 ± 2 1.5 ± 0.1 7  0.1 (0.02-0.6)  0.6 (0.5-1.1)  0.6 (0.5-0.O-1656

DMH H 18 ± 1   2 ± 0.2 9  1.5 (0.4-7.0)  1.2 (0.9-1.5)  0.6 (0.1-8.O-1660

DMH H  7 ± 1   3 ± 0.8 2  3.5 (3.2-3.8)  2.4 (1.9-3.0)  4.6 (2.4-9.O-1425

DMH H 153 ± 17 12 ± 2  13  17  (10-29) 15  (10-24) 13 (10-19) O-1661

DMH H 138 ± 4  28 ± 12 5 24  (13-42) 14  (9-20) 24  (17-34) O-1662

DMH H >10,000 5424 ± 1103 — 87% (30) 30% (30) −3 (30) O-1423

DMH H 97 ± 5 28 ± 5  3 12  (8-20) 9  (7-13) 9  (6-15) O-2010

H C₆H₁₃ 9515 ± 332 NT — −18% (30) 9% (30) −0.4 (30)The K_(i)'s are presented as means ± SEM. All ED₅₀'s are expressed asμmol/kg (with 95% confidence limits in parentheses). For compounds thatfailed to produce either maximal or dose-related effects, the percenteffect at the highest dose (mg/kg: in parenthesis) is provided. SA =suppression of spontaneous activity: MPE = % maximum possibleintinociceptive effect in tail flick assay: RT = rectal temperature.

TABLE 3 In Vitro and In Vivo Cannabinoid Effects Bicyclic Resorcinolswith Methylated Cyclohexane

K_(i)(nM) CB₁/ ED₅₀ ID R R1 CB₁ CB₂ CB₂ SA TF RT O-1658

DMH 16 ± 2  1 ± 0.3 16 0.2 (0.1-0.3) 0.3 (0.2-0.3) 0.3 (0.27-0.5 O-1659

DMH 45 ± 1  5 ± 0.9 9 4.8 (3-9) 3.9 (3-6) 3.3 (2-5) O-1663

DMH 144 ± 22 9 ± 2  16 32% (30) 7% (30) −2.2 (30) O-1657

DMH   14 ± 0.5 0.8 ± 0.04 17 0.3 (0.3-0.5) 0.6 (0.5-1) 0.9 (0.7-1.1)O-1797A

DMH   5 ± 0.6 0.4 ± 0.03 12 0.5 (0.4-0.6) 1.1 (0.8-1.5) 0.7 (0.6-1.0)O-1798B

DMH   4 ± 0.6 0.5 ± 0.07 8 0.2 (0.03-12) 1.0 (0.7-1.6) 0.6 (0.5-0.7)O-1826

DMH  40 ± 11 0.8 ± 0.05 50 2.7 (2.1-3.9) 2.4 (1.8-3.3) 3.6 (2.7-4.5)O-1890

DM-butyl 96 ± 4 13 ± 1   7 69  (55-90) 48  (31-69) 72  (45-114) O-1871

DMH   2 ± 0.3 0.3 ± 0.01 7 <1.0* 2.3 (2.0-2.6) 1.3 (0.3-4.3)*This dose (μmol/kg) produced > 50% inhibition and was the lowest dosetested. The K_(i)'s are presented as means ± SEM. All ED₅₀'s areexpressed as μmol/kg (with 95% confidence limits in parentheses). Forcompounds that failed to produce either maximal or dose-related effects,the percent effect at the highest dose (mg/kg: in parenthesis) isprovided. SA = suppression of spontaneous activity; MPE = % maximumpossible antinociceptive# effect in tail flick assay: RT = rectal temperature.

TABLE 4 CB₁ and CB₂ Binding Affinities of Dimethoxy-DimethylheptylResorcinol Analogs

CH₂OH K_(i)(nM)* ID R CB₁ CB₂ CB₁/CB₂ 22 HU-308^(a)

>10,000 23 ± 4 — 23 O-1999

>10,000  466 ± 110 — 24 O-1964

>10,000  911 ± 116 — 25 O-1965

>10,000 >10,000 — 26 O-1962

>10,000 342 ± 22 — 27 O-2092

4581 ± 312 126 ± 12 36 28 O-2122

3758 ± 184 1065 ± 107  4 29 O-2114

8442 ± 954 1773 ± 184  5 30 O-2115

4572 ± 173 346 ± 49 13 31 O-2123

1731 ± 117 125 ± 14 14*The K_(i)'s are presented as meana ± SEM.^(a)Values from Hanu_et al,. 1999.Note:Binding ligand. [³H ]HU-243, was different from that used in presentstudy.

TABLE 5 CB₁ and CB₂ Binding Affinities of HydroxylatedDimethoxy-Dimethylheptyl Resorcinols

K₁ (nM) ID R R1 R2 CB₁ CB₂ CB₁/CB₂ 32 O-2072

OCH₃ DMH 5820 ± 662  105 ± 19   55 33 O-1966A

OCH₃ DMH 5055 ± 984   23 ± 2.1 220 34 O-1967B

OCH₃ DMH 1716 ± 105  111 ± 8   15 35 O-2121

OCH₃ DMH 1990 ± 77  101 ± 14   20 36 O-2116A

OCH₃ DMH 3932 ± 483  190 ± 17   21 37 O-2117B

OCH₃ DMH >10,000 1561 ± 70  — 38 O-2068

OCH₃ DMH 7515 ± 721  161 ± 24   47 39 O-2139

OCH₃ CH₃ >10,000 >10,000 — 40 O-2090

OC₂H₅ DMH 8810 ± 422  858 ± 43   10 41 O-2091

OCH₃ DMH 3201 ± 141  64 ± 8   50The K₁ 's are presented as means ± SEM.

A C D I J K L M N 1 RAZDAN STRUCTURE CB1 KI CB2 KI S.A. T.F. R.T.Publication 2 O# (nM) (nM) ED50 (mg/kg) or % effect at dose 3 O-1376O-1376 = 3-1′,1′-Dimethylhepty-6- (2-isopropyl-5- methylphenyl)phenol

32.7 ± 4.0 2.63 ± 0.36 2.944 1.97 0.822 Wiley et al. (in press) 4 O-1422O-1422 = Cyclohexyl-5-(1′,1′- dimethylheptyl)-resorcinol

11.33 ± 2 1.46 ± 0.1 0.3794 0.2412 0.19394 Wiley et al. (in press) 5O-1423 O-1423 = 2-(Cyclohex-1′-enyl)-5- (1′,1′-dimethylheptyl-resorcinol

96.65 ± 5 27.62 ± 5.13 3.918 2.856 2.944 Wiley et al. (in press) 6O-1424 O-1424 = 2-(Cyclopentyl)- dimethylheptyl-resorcinol

94.88 ± 6 6.66 ± 0.43 8.294 4.481 4.239 Wiley et al. (in press) 7 O-1425O-1425 = 2-(4- Tertrahydrothiopyranyl)-5-(1′,1′-dimethylheptyl-resorcinol

152.84 ± 17 12.18 ± 2.09 5.819 5.049 4.526 Wiley et al. (in press) 8O-1532 3-1′,1′-Dimethylbutyl-6-(2- isopropyl-5-methyl-phenyl)-phenol

876 ± 18.45 112.6 ± 21 Wiley et al. (in press) 9 O-16013-1′,1′-Dimethylhepyl-6-(2- isopropyl-5-hydroxy- methylphenyl)-phenol

4.82 ± 0.56 2.91 ± 0.43 Wiley et al. (in press) 10 O-1602(−)-4-(3,3,4-trans-p-Menthadian- (1,8)-yl-orcinol

>10,000 >10,000 66% stim. @ 30 0 @ 30 0.3 @ 30 11 O-16562-Cycloheptyl-5-(1′,1′-dimethyl- heptyl)-resorcinol

17.8 ± 1.4 2.12 ± 0.25 0.53 0.39 0.21 Wiley et al. (in press) 12 O-16572-(3-Methylcyclohexyl)-5-(1′, 1′-dimethylheptyl)-resorcinol

14.4 ± 0.53 0.82 ± 0.04 0.13 0.23 0.29 Wiley et al. (in press) 13 O-16582-(2-Methylcyclohexyl)-5-(1′, 1′-dimethylheptyl)-resorcinol

16 5 ± 1.7 1 38 ± 0 33 0.06 0.09 0.12 Wiley et al. (in press) 14 O-16592-(4-Methylcyclohexyl)-5-(1′, 1′-dimethylheptyl)-resorcinol

45 22 ± 52 4 73 ± 0 94 1.65 1.35 1.12 Wiley et al. (in press) 15 O-16602-(2-Adamantanyl)-5-(1′,1′-di- methylheptyl)-resorcinol

7.5 ± 1.2 3.16 ± 0.81 1.273 0.911 1.729 Wiley et al. (in press) 16O-1661 2-(Tetrahydrothiophen-3-yl)- 5-(1′,1′-dimethylheptyl)-resorcinol

138 ± 3.7 27.7 ± 12.1 7.648 4.389 7.781 Wiley et al. (in press) 17O-1662 2-(1-Methylpiperidin-4-yl)- 5-(1′,1′-dimethylheptyl)-resorcinol

>10,000 5424 ± 1103 77% stim @ 10 7 @ 10 1 @ 10. Lethal @ 30 Wiley etal. (in press) 18 O-1663 2-(4-Phenylcyclohexyl)-5-(1′,1′-dimethylheptyl)-resorcinol

143.7 ± 21.9 8.8 ± 1.6 32% @ 30 7% @ 30 neg 2.2 @ 30 Wiley et al. (inpress) 19 O-1797 2-(3-Methylcyclohexyl)-5-(1′,1′-dimethylheptyl-resorcinol isomer A

5.21 ± 0.57 0.44 ± 0.03 0.154 0.362 0.252 Wiley et al. (in press) 20O-1798 2-(3-Methylcyclohexyl)-5-(1′,1′- dimethylheptyl)-resorcinolisomer B

4.33 ± 0.58 0.48 ± 0.07 0.070 0.379 0.218 Wiley et al. (in press) 21O-1821 (-)-2-(3-3,4-trans-p-menthadien-(1,8)- yl)-orcinol

>10,000 0 @ 30 3 @ 30 neg 1 @30 22 O-18262-(3R-Methylcyclohexyl)-5-(1′,1′- dimethylheptyl)-resorcinol

40 ± 10.9 0.8 ± 0.05 0.915 0.821 1.162 Wiley et al. (in press) 23 O-1847(-)-2-(3-3,4-trans-p-menthadien- (1,8)-yl)-resorcinol

>10,000 24 O-1848 (-)-4-(3-3,4-trans-p-menthadien- (1,8)-yl)-resorcinol

>10,000 25 O-1868 (-)-2-(3-3,4-trans-p-menthadien-(1,8)-yl)-1,6-dipdoorcinol

>10,000 26 O-1871 2-(3,3-Dimethylcyclohexyl-5-(1′,1′-dimethylheptyl)-resorcinol

2.3 ± 0.32 0.3 ± 0.01 0.04 0.7 0.37 27 O-18902-(3-Methylcyclohexyl)-5-(1′,1′- dimethylbutyl)-resorcinol

96.1 ± 3.53 13.2 ± 1.4 20 14 21 28 O-19172-Cyclohexyl-5-methyl-resorcinol

29 O-1918 (-)-1,3-Dimethoxy-2-(3-3,4-trans-p-manthadion-(1,8)-yl)-orcinol

30 O-1919 (-)-2-(3-3,4-trans-p-manthadion- (1,8)-yl)-manomethoxy orcinol

31 O-1962 O-1962 4-[4-(1,1-Dimethyl-heptyl)-2,6-dimethoxy-phenyl]tetrahydropyran- 4-ol

>10,000 342 ± 22.4 36% @ 30 23% @ 30 neg 0.9 @30 Wiley et al. (in press)32 O-1964 O-1964 4-[4-(1,1-Dimethyl-heptyl)-2,6-dimethoxy-phenyl]tetrahydropyran

>10,000 911 ± 116 neg 1.9 @30 30% @ 30 neg 0.6 @30 Wiley et al. (inpress) 33 O-1965 O-1965 4-[4-(1,1-Dimethyl-heptyl)-2,6-dimethoxy-phenyl]-3,6-dihydro- 2H-pyran

>10,000 >10,000 Wiley et al. (in press) 34 O-1966 O-19661-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-3-methyl- cyclohexanolisomer 1

5055 ± 983.8 23 ± 2.1 neg 19.0 @30 5.1 @ 30 0.5 @ 30 Wiley et al. (inpress) 35 O-1967 O-1967 1-[4-(1,1-Dimethyl-heptyl)-2,6-dimethoxy-phenyl]-3-methyl- cyclohexanol isomer 2

1716.3 ± 104.8 111 ± 7.8 42.9 @ 30 8.2% @30 0 @ 30 Wiley et al. (inpress) 36 O-1999 O-1999 5-(1,1-Dimethyl-heptyl)-1,3-dimethoxy-2-(3-methyl- cyclohexyl)-benzeno

>10,000 465.6 ± 110 4 @ 30 6 @ 30 1 @ 30 Wiley et al. (in press) 37O-2010 O-2010 2-Cyclohexyl-4-hexyl resorcinol

9515 ± 332.5 neg 17.7% @ 30 9.0% @ 30 neg 0.4 @30 Wiley et al. (inpress) 38 O-2068 O-2068 1-[4-(1,1-Dimethylheptyl)-2,6-dimethoxyphenyl]3,3-dimethyl- cyclohexanol

7515 ± 720.9 161.48 ± 24.31 Wiley et al. (in press) 39 O-2072 O-20721-[4-(1,1-Dimethylheptyl)-2,6- dimethoxyphenyl]-cyclohexanol

5820.33 ± 662.31 105.36 ± 18.66 Wiley et al. (in press) 40 O-2090 O-20901-[4-(1,1-Dimethylheptyl)-2,6- dietlphenyl]-3-methyl cyclohexane- 1-ol

8809.67 ± 422.15 857.67 ± 42.97 Wiley et al. (in press) 41 O-2091 O-20911-[4-(1,1-Dimethylheptyl)-2,6- dimephenyl]-cycloheptan-1-ol

3200.67 ± 141.04 63.83 ± 8.21 Wiley et al. (in press) 42 O-2092 O-20928-[4-(1,1-Dimethylheptyl)-2,6- dimephenyl]-1,4- dioxaspiro[4,5]decan-

4581.33 ± 311.65 125.53 ± 12.45 Wiley et al. (in press) 43 21144-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-cyclohex-3- enone

8441.7 ± 954.3 1772.7 ± 183.7 Wiley et al. (in press) 44 21154-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-4-hydroxy- cyclohexane

4571.7 ± 173.4 345.7 ± 48.8 Wiley et al. (in press) 45 21161-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-cyclohexane- 1,4-olol(A)

3931.7 ± 483.4 190.3 ± 17.0 Wiley et al. (in press) 46 21171-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-cyclohexane- 1,4-olol(B)

>10,000 1561.3 ± 69.7 Wiley et al. (in press) 47 2118 Name of structurenot given, also structure needs an arrow Presently its drawn with MWformula C22H30O3, should be C24H32O3

6444.3 ± 1389.5 3352 ± 253.2 48 2121 1-[4-(1,1-Dimethyl-heptyl)-2,6-dimethoxy-phenyl]-5-methyl- cyclohexane-1,3-olol

1990 ± 76.66 100.67 ± 13.88 Wiley et al. (in press) 49 21226-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-7-oxa- bicyclo[4 10]heptan-3-ol

3757.67 ± 184.15 1065 ± 107.08 Wiley et al. (in press) 50 21233-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-3-hydroxy-5-methyl-cyclohexanone

7330.67 ± 116.86 124.93 ± 14.40 Wiley et al. (in press) 51 2137 O-21371-[4-(1,1-Dimethyl-heptyl)-2,6- dimethoxy-phenyl]-3-methyl- cyclohexanol

2665 ± 145.31 11.04 ± 2.18 52 2139 O-2139 1-(2,6-Dimethoxy-4-methyl-phenyl)-3,3-dimethyl-cyclo- hexanol

>10,000 >10,000 Wiley et al. (in press) 53 O-22981-(2,6-Dimethoxy-4-methyl- phenyl)-cyclohexanol

>10,000 >10,000 54 O-2299 2-Cyclohexyl-1,3-dimethoxy- 5-methylbenzene

>10,000 >10,000

1. A compound of general formula I

wherein: R is selected from the group consisting of optionallysubstituted carbocyclic and heterocyclic rings; R1 is independentlyselected at each occurrence from the group consisting of hydrogen andC₁₋₆ alkyl; R4 is selected from the group consisting of C₁₋₁₀ alkyl andalkenyl; and a pharmaceutically acceptable salt, ester and tautomerthereof.
 2. A compound as claimed in claim 1 wherein R is optionallysubstituted aryl.
 3. A compound as claimed in claim 2 wherein said arylis selected from the group consisting of phenyl, cyclohexyl,cycloheptyl, cyclohexenyl, cyclopentyl, tetrahydrothiopyranyl,methandienyl, cycloheptyl, adamantanyl, tetrahydrothiophen-3-yl,1-alkyl-piperidinyl, 4-arylcyclohexyl, 3,3-dialkylcyclohexyl,tetrahydropyranyl, 1-cyclohexanolyl, 1-4-dioxospirocycloalkyl andcyclohex-3-enonyl.
 4. A compound as claimed in claim 1 wherein R1 ishydrogen or methyl.
 5. A compound as claimed in claim 1 wherein R4 islinear C₅₋₇ alkyl.
 6. A compound as claimed in claim 5, wherein R4 ishexyl.
 7. A compound of general formula II:

wherein R1 is independently selected at each occurrence from the groupconsisting of hydrogen and C₁₋₆ alkyl; R4 is selected from the groupconsisting of C₁₋₁₀ alkyl and alkenyl; and R5 is C₁₋₆ alkyl.
 8. Acompound as claimed in claim 7, wherein R5 is methyl or ethyl.
 9. Acompound as claimed in claim 7 wherein R1 is hydrogen or methyl.
 10. Acompound as claimed in claim 7, wherein R1 is hydrogen.
 11. A compoundof the formula


12. A compound selected from the group consisting of:2-(3-methylcyclohexyl)-5-(1,1′-dimethylheptyl)-resorcinol;2-(3-methylcyclohexyl)-5-(1,1′-dimethylheptyl)-resorcinol; and2-(3R-methylcyclohexyl)-5-(1,1′-dimethylheptyl)-resorcinol.
 13. Acomposition comprising a compound of formula I, together with apharmaceutically acceptable carrier and/or excipient.
 14. A compositioncomprising a compound of formula II together with a pharmaceuticallyacceptable carrier and/or excipient.
 15. A method of treating paincomprising administering to a patient in need thereof a therapeuticallyeffective amount of a compound of formula I.
 16. A method of treatingpain comprising administering to a patient in need thereof atherapeutically effective amount of a compound of formula II.
 17. Amethod as claimed in claim 13, wherein said pain is peripheral pain. 18.a composition comprising a compound of formula I or II together with apharmaceutically acceptable carrier and/or excipient. The compositionshould be sterile and, if intended for injection, non-pyrogenic
 19. Amethod of treating inflammation comprising administering to a patient inneed thereof a therapeutically effective amount of a compound of formulaI.
 20. A method of treating inflammation comprising administering to apatient in need thereof a therapeutically effective amount of a compoundof formula II.
 21. A method of treating autoimmune disease comprisingadministering to a patient in need thereof a therapeutically effectiveamount of a compound of formula I.
 22. A method of treating autoimmunedisease comprising administering to a patient in need thereof atherapeutically effective amount of a compound of formula II. 23 Acompound of formula I for use in therapy.
 24. Use of a compound offormula 1 for the manufacture of a medicament for the treatment of apain, inflammation and autoimmune disease.